I. Field of the Disclosure
The technology of the disclosure relates generally to power charging circuitry for mobile terminals.
II. Background
Computing devices, and particularly mobile computing devices, have become common throughout society. Over one billion mobile computing devices were sold in 2010 with no saturation of demand in sight. Mobile computing devices derive their ability to be mobile through the use of increasingly efficient and small rechargeable battery devices. Such rechargeable battery devices must be recharged from an external power source. The most common such external power source is a wall outlet. However, as the number and variety of computing devices have increased, alternate power sources and power formats have been adopted as viable power sources for mobile computing devices.
An example of such an alternate power source and alternate power format is the use of a computing device to provide power to the mobile computing device through a Universal Serial Bus (USB) cable or USB plug. Still another possible power source is through a wireless interface. Regardless of source, most mobile computing devices require that the battery be recharged using a direct current (DC) voltage provided at a specific current and/or voltage profile. To force compliance with such requirements, a charging circuit may be provided within an integrated circuit (IC) within the mobile computing device. Such charging circuits typically include a buck converter.
As the number of possible power sources increases, designers have contemplated providing dedicated charger circuits for the mobile computing device. Such dedicated charger circuits may consume relatively large volumes within the mobile computing device and impose power penalties. Even if the charger circuit allows for operation with two power sources, there may be other power sources for which a designer desires interoperability. Thus, there needs to be more flexibility in providing charger circuits.